Dominican Father Gustavo Gutierrez is pictured in 2007 on the campus of the University of Notre Dame in Indiana. Father Gutierrez, known as the father of liberation theology, had an informal meeting with Pope Francis Sept. 11 at the pontiff's residence, Domus Sanctae Martae.

VATICAN CITY — Pope Francis' Sept. 11 meeting with Dominican Father Gustavo Gutierrez was an informal one, held in the in the pope's residence, the Domus Sanctae Marthae, and not listed on his official schedule. Yet the news that Pope Francis had received the 85-year old Peruvian priest, who is widely considered the father of liberation theology, has excited interest far beyond the Vatican's walls.

During the 1990s, the Congregation for the Doctrine of the Faith conducted a lengthy critical review of Father Gutierrez's work, and required him to write and rewrite articles clarifying some of his theological and pastoral points.

But within a single week in early September 2013, the Vatican newspaper, L'Osservatore Romano, published an interview with Father Gutierrez, an article by the theologian himself, and two articles praising his work -- one of them by the prefect of the Congregation for the Doctrine of the Faith, Archbishop Gerhard L. Muller.

Following years of Vatican criticism of liberation theology under Blessed John Paul II and Pope Benedict XVI, these events might seem to indicate a reversal of policy under Pope Francis. It would be more accurate to say they represent the fruit of a long and painful process, through which the church has clarified the nature of its commitment to the world's poor today.

Liberation theology emerged in Latin America in the 1960s and 1970s. It finds in Scripture the principles and inspiration for working to free people from unjust social patterns and structures. Its starting point often is the concrete situation of Latin America's predominantly poor people and how they understand the Scriptures as relating to them in their struggles for freedom from sin and from unjust social structures.

During the 1980s, the Vatican's doctrinal office under then-Cardinal Joseph Ratzinger, the future Pope Benedict, issued two major documents on liberation theology. The documents praised the movement's concern for the poor and for justice, but condemned a tendency to mix Marxist social analysis and concepts such as "class struggle" with religious commitments to end poverty and injustice.

The consequences of theologians adopting Marxist methods, Pope Benedict later told Brazilian bishops, included "rebellion, division, dissent, offense (and) anarchy," which were still "creating great suffering in your diocesan communities and a serious loss of vital energy."

On another occasion, he told an interviewer that the "politicization of the faith" by some liberation theologians had contributed to the "widespread exodus" of Latin American Catholics to Pentecostal and other Protestant churches.

Many Jesuits embraced liberation theology as part of what a 1975 decree by the order called their "commitment to promote justice and enter into solidarity with the voiceless and the powerless."

Not surprisingly, any signs of sympathy with secular ideas of revolution drew concern from the Vatican. In 2007, the doctrinal congregation warned of "erroneous or dangerous propositions" in the work of Jesuit Father Jon Sobrino. The following year, Pope Benedict found it necessary to ask the Jesuits as an order to reaffirm their adherence to church teaching on a number of controversial questions, including "some aspects of the theology of liberation."

As superior of the Jesuits' Argentine province from 1973 to 1979, then-Father Jorge Mario Bergoglio discouraged politicization among his priests, especially during the military dictatorship that took power in Argentina in 1976. In the polarized atmosphere within the order, he was hardly counted as a friend of liberation theology.

But the future pope's pastoral work for and with the poor was constant, and would eventually find expression at the Fifth General Conference of the Bishops of Latin America and the Caribbean, held in 2007 in Aparecida, Brazil.

The conference's concluding document, of which then-Cardinal Bergoglio was a principal author, did not use the term "liberation theology," but its strong words about the "building of a just and fraternal society" that ensures "health, food, education, housing and work for all" reflect the spirit of the movement in its orthodox version.

Pope Francis' election was thus a powerful affirmation of the belief that the pursuit of social justice is a necessary consequence of Christian faith. But less than nine months before the papal conclave, a less heralded appointment had already signaled that this belief, as formulated in liberation theology, enjoyed favor at the church's highest levels.

When Pope Benedict named Archbishop Muller to head the doctrinal office, in July 2012, he surely knew that the man he was making the highest custodian of church teaching after the pope himself was an admirer and co-author of none other than Father Gutierrez.